TheSamba.com :: View topic - Lights and Signals (1971 Bay Window Bus-type II)

Fri Oct 30, 2009 10:48 am

There are two brake light switches on the master cylinder - one connected to each section, as it's a dual cylinder. The brake check light comes on if both switches don't act in unison - either both off or both on.

This means that if the light is lit, one hydraulic circuit has malfunctioned or that one switch is bad or has bad connections. Try bleeding the brakes.

Re: the rear light issue, Busdaddy is correct - failed ground connections. Any time that turning headlights on or off affects turn signals or brake lights, it's always the ground connections. It's the only thing the two circuits have in common.

Fri Oct 30, 2009 10:57 am

^^ A clear explanation of the brake light switches.

Was the bus sitting for a while before you bought it?

Fri Oct 30, 2009 11:16 am

Thanks for the info on the brake light switches. Do you think the master cylinder is shot?
Where would these ground connections be at?

thanks again

the bus was sitting and only driven every once in awhile on short drives

Fri Oct 30, 2009 11:16 am

telford dorr wrote: There are two brake light switches on the master cylinder - one connected to each section, as it's a dual cylinder. The brake check light comes on if both switches don't act in unison - either both off or both on.

This means that if the light is lit, one hydraulic circuit has malfunctioned or that one switch is bad or has bad connections. Try bleeding the brakes.

Re: the rear light issue, Busdaddy is correct - failed ground connections. Any time that turning headlights on or off affects turn signals or brake lights, it's always the ground connections. It's the only thing the two circuits have in common.

I agree Telford, but the dash warning light is only coming on when he turns on the headlights, although he may indeed have brake problems too the light usually only comes on when you step on the brakes if there's an issue. Resolve the funkyness in the rear before you get in over your head, it could possibly be a backflow of current from a bad socket or bulb.

Fri Oct 30, 2009 11:18 am

Spicoli Bus

Do this. First get up under there and look at your master cylinder's two switches and all the wiring that goes from them up to the dash. Pull the connections off both and clean the switch connections up like what you're gonna do with the tail lights. While you're down there, take a good look at the resevoir that sits on top of the master cylinder. Is it leaking? Or was the loss of brake fluid from some other source??? Keep us posted and let us know what you find out once all electrical is cleaned up...

Fri Oct 30, 2009 11:23 am

Jody 71,

Good ideas! This forum is great because of all of you helpful people on it.
I will work on it after work and update the forum tomorrow.
thanks!

Fri Oct 30, 2009 11:34 am

This may be a stupid question, but where are these ground connections I need to fix?

Fri Oct 30, 2009 11:44 am

It's really odd that my original '71 owner's manual shows the location of the brake warning light switch to be at the top to the right of clock hole, but on my Westy, it's at the bottom. Did Transporters and Westy's have different locations? Or, did the location change somewhere during the '71 production year run? Mine is November 1970.

Fri Oct 30, 2009 11:46 am

If your Bus is wired correctly, with your tailights the ground wires are brown.

Fri Oct 30, 2009 11:51 am

My light is at the bottom and I believe it was made in March. My VIN starts 2312 (not sure if this is the date or not)?

Fri Oct 30, 2009 11:53 am

any idea why my bus likes to stall when stopping at a light or stop sign? Maybe spark plugs, tune-up; that sort of thing? It idles fine though when not driving

Fri Oct 30, 2009 12:05 pm

Jody '71 wrote: It's really odd that my original '71 owner's manual shows the location of the brake warning light switch to be at the top to the right of clock hole, but on my Westy, it's at the bottom. Did Transporters and Westy's have different locations? Or, did the location change somewhere during the '71 production year run? Mine is November 1970.

The location is the same westy or bus, but the light did move in early 71.

Mr. Spicoli, The stalling could be a few things, the most likely are idle mixture wrong (possibly lean) or plugged preheat tubes running under the manifold, lack of aircleaner preaheat can also contribute to this.

Fri Oct 30, 2009 12:11 pm

how do you change the "lean" mixture? with idle carb adjustments?
what about the two tubes running from either side of the fan compartment to the muffler; mine are not attached to the muffler in any way

Fri Oct 30, 2009 12:23 pm

As B-Daddy says, anything can be causing issues for the symptons you describe. Some really nice clear pics of your engine compartment would help the membership a lot, and DO take lots at different angles, and we need to see if your tinware is intact and if you have a nice engine to body seal in place. Please make sure to include the carb and distributor. A few pics of your master cylinder will help. You are on the right track by keeping the Samba informed. A Bentley manual for your Bus is an absolute must have.

Fri Oct 30, 2009 12:31 pm

I will get some pics for everyone to look at, maybe tomorrow... until then

Fri Oct 30, 2009 1:09 pm

busdaddy wrote: I agree Telford, but the dash warning light is only coming on when he turns on the headlights, although he may indeed have brake problems too the light usually only comes on when you step on the brakes if there's an issue. Resolve the funkyness in the rear before you get in over your head, it could possibly be a backflow of current from a bad socket or bulb.

If there was a bad ground, power would indeed back-feed from the tail light circuit through the brake light bulb back to the switch.

<looking it up...>

OK, looked it up: power backfed to the brake switches will cause the light to light up. So the grounds at the rear need to be fixed first. I buff all connection lugs with a small wire brush on a Dremmel tool, then seal with a little silicone grease.

And indeed, for sanity's sake, fix one thing at a time until it works, then move on to the next location. Avoids the 'snowball effect'...

Tue Nov 03, 2009 10:12 am

Okay, I have done a few things. I bled all four brakes and adjusted the rear brakes. (actually only one because the left rear stars would not budge and actually bent the screwdriver). Cleaned ground wires but I have all kinds of wires not attached and just laying around which worries me.
I checked the master cylinder and yep the switch wires are severed from the the switch and the cylinder has a small hole or something cause it is leaking. bummer

Tue Nov 03, 2009 10:23 am

OK, at least you have a clear cause of the problem. Compare all wiring to the Bentley schematic, and restore to stock. You should then be good to go.

Tue Nov 03, 2009 10:45 am

Anybody have tips on installing a master cylinder? Like; drain the brake fluid first and things like that.... should be somewhat easy?